Sidewalk.



No. 672,822. Patented Apr. 23, IBM.

w. L. CA LDWELL.

SIDEWALK.

(Application filed Sept. 15, 1900.) (No Model.)

9 WJL'W KM UNITED STATES PATENT Fries.

WILLIAM LWOALDWELL, OF NEW YORK, N. Y., ASSIGNOR OF TWO-THIRDS TO JOHNW. RAPP AND HENRY LOY EASTON, OF SAME PLACE.

SI'DVEWALK.

SPECIFICATION forming part of Letters Patent No, 672,822, dated April.23, 1901. Application filed September 15, 1900 Serial No. 30,119. (Nomodel.)

To aZZ whom it may concern.-

Be it known that LWILLIAM L. CALDWELL,

. a citizen of the United States, residing at New sidewalks; and itsobject is to provide a sidewalk composed of a cement body with asheetmetal support, the latter being sufficiently yielding to permit ofits expansion and contraction under changes of temperature with- .outfracture due to the rigidity of the cement, while at the same timeaffording sufficient vertical support.

My invention also provides for a luminous or lighted construction, thestructure being channeled, with comparatively thin portions for thereception of the glass lights or blocks and heaviest intermediateportions for support.

In the accompanying drawings, Figure 1 is a perspective view of aportion of the improved pavement. Fig. 2 is a vertical section thereof.Fig. 3 is a detail view of one of the lights.

The construction comprises a plate or sheetmetal support or form 1, withparallel corrugations, so as to form channels 2 2 in opposite sides withintermediate flat or plane portions 3 3. This sheet-metal support orform is placed with its ends resting on the bases or substructures 4 ofthe pavement, with the corrugations extending longitudinally across fromone base 4E to the other. In the flat portions 3 at the top are providedapertures 5, of any suitable shape, for the reception of lights or glassblocks 6, of corresponding shape, such blocks being preferably providedwith a lower part fitting in such apertures and with an upper extensionof larger size extending over the form 1 sufficiently to support theblock. These lights having been put in place, the form 1 is covered withcement 6, filling all the upturned channels 2 and covering the upperflat portions 3 to the level of the top of the lights. This results in aconstruction consisting of longitudinal girders or stringers 7, ofcement, supported and contained by the troughs or channels 2' of sheetmetal, and intermediate comparatively thin web portions 8, including theupper flat portions 3, the superimposed cement, and the lights 6. Theunder channels 2 then serve as passage-ways for the light passingthrough the glass blocks.

Owing to the yielding nature of the sheetmetal support or form 1 it isnot so liable to crack the cement or to be itself disrupted by thestrains due to expansion or contraction of the metal. The depth of thechannels may be made sufficient to give a contained girder of cement ofsufficient height to withstand with the support furnished by thenearlyvertical sides of the channel any required load. A great advantageof my improved construction is that it dispenses with the use of anyfalse work for centering or bridging, the

part 1 serving first as a mold or form for the cement and afterward as asupport to aid in sustaining the weight. The portions 3 of the plate orform 1 that form the bottoms of the channels 2 are flat or plane, so asto form flat bearing-surfaces adapted to rest directly on the sidebearing-supports and take the Weight of the structure without anydistortion or bending such as would occur with a roundedbearing-surface. Moreover, this flat bottom portion 3 where it meets theplane substantially vertical portions which formthe sides of thechannels 2 forms decided 8o angles, which resist any tendency of theocment to creep or slide on the form 1 laterally during the changes ofload, and therefore serve to maintain the integrity of the structure,which is essential to strength and durability. The top faces of theplate or form 1 where they meet the plane sides of the channels alsoform angles resisting any creeping tendency. With a rounded bottom orsup port the tendency of the cement to creep 9o thereon during changesof load is only resisted by the adhesion of the cement and is liable toexceed the adhesive capacity of the structure, loosening the cement fromthe support and weakening the structure, so as to render 5 it uselessand dangerous. The substantial or approximate verticality of the sidewalls of the channels is also of importance, as it onables the cement toobtain such a hold on the support and is accompanied with such slight10o flexions under changes of load that the cement is enabled to retainits adhesive grip under all reasonable changes of load, and a permanentpractically inseparable structure is produced without the use of crossstays or ties or special supporting-saddles. If the cement-receivingchannels were made to flare upwardly at a very decided angle, the amount,of distortion produced on even moderate changes of load would besufficient to part the cement-from the support, and this effect would beheightened if accompanied by a rounded conformation of the channel, forthe reasons above stated. It has been proposed to avoid such separationof the parts by making the channel dovetailed; but in that case theconstruction is mechanically bad, as it brings the minimum thickness ofcement at the neutral axis--that is, about half-way between the bottomand top of the cement,where splitting of the cement is most likely tooccur. The best construction mechanically is that in which the cementbeams taper upwardly,so as to permit the maximum thickness in thecompressive portion, and by my invention I obtain such a construction bya slight upward flare without departing from the vertical sufficientlyto cause the cement and metal support to part on changes of load, asaforesaid. While the lights 6 are held by the under side projections inthe holes in the top of the form 1 sufliciently to retain them in placeduring the cem'enting operation, it is the cement itself that finallyholds them in position. This is of advantage, in that the thermalexpansion of glass and cement being about equal a tight joint ismaintained, obviating the liability to leakage or loose lights. The topof the light 6 is beveled 'on the edges, as shown at 9, so

that when the cement is in place it serves to hold the glass morefirmly.

What I claim as new, and desire to secure by Letters Patent, is-

1. A sidewalk construction, comprising a with the plane sides, andcement filling in the channels on the upper sides, forming girders. 3. Asidewalk construction, comprising a sheet-metal form shaped withchannels above and below, with flat portions, between the channels onthe upper side, provided with apertures, lights in said apertures andextending above same, and cement filling in the channels on the upperside, extending over said flat portions between the lights, so as to besubstantially flush with the lights, the bottoms of the lower channelsbeing provided with flat bearing-faces, and the cement-receivingchannels having substantially vertical sides with a slight upward flare.

WILLIAM L. OALDVVELL.

Witnesses:

A. P. KNIGHT, J. GREEN.

